Can't see it for some reason (maybe Britishness ;) but it's io9 calling it a trailer, not Marvel (who say "...Marvel.Com unveils a very special episode of the critically-acclaimed Marvel Super Heroes: What Theó?! video series, taking you behind the scenes of what could've been!").

So, using the words as clues (and as I say, without actually seeing it) i'd assume it's a joke extra feature along the lines of the "outtakes" from "Toy Story" or "Monsters Inc.". Not, to reiterate, a trailer for anything.

Yeah, they're making a motion comic of 'Gifted' (it's been linked about from here a few times) but no, i'm betting this isn't meant to be a trailer for it (as I say, only io9 are calling it that, not Marvel. Who you might assume would know ;) but is instead a jokey promotional tool.

Heh, yeah, I sort of like this more than the actual trailers I've seen for the project. It sort of makes me wish that they just handed it over to Seth Green and the other Robot Chicken folk to make a stop motion animated parody of the storyline.